Pierre Boullioux runs the legendary Sup-Air and has been involved in the development of paragliders and equipment from the start. His article in the french Parapente Mag. in 1990 was the first thing I read that actually helped me to control the paraglider and he was kind enough to give me copies of his original notes from which the piece below was generated. Although it is a little dated there is still much to learn from it although in some modern canopies the optimum recovery technique may be slightly different to that described below. This is an adaptation rather than a straight translation partly because the notes were a bit mixed up and partly because of the limitations of my french. I hope I have done it some justice.

Adapted from an article by Pierre Boullioux.

Thankfully modern canopies are much less susceptible to closures than those of only a few years ago and pilots less readily aquire experience of closures. This makes SIV training and theoretical understanding much more important.

Turbulence makes the effective angle of attack of the canopy vary randomly. The angle of attack is maximum at the point of stall and minimum at the point of closure. Safety in rough air depends on the ability of the pilot to control the angle of attack by reacting quickly to incipient closures.

A 'pump' on the brakes momentarily;

• Accentuates the curvature of the profile.
• Increases lift.
• Increases tension along and across the wing.
• Increases internal pressure.
• Increases angle of attack.
• 'Flicks up' the leading edge.

Anticipation of the need for a pump to limit surging or inhibit tucking will increase the effectiveness of the pump. i.e. The earlier a pump is made the less powerful it needs to be. Airspeed control 'by ear' enables the pilot to ensure an adequate and suitable airspeed is maintained.

In rough air or when entering strong lift the canopy may surge forwards or backwards above the pilot. (Or the pilot swing backwards and forwards under the canopy if you prefer.) A forward surge can be limited by a rapid pump of the brakes.

Backward movement of the canopy should be countered by releasing the brakes to allow the canopy to surge forward. This surge may result in the canopy 'overshooting' and need to be checked with a pump. Very rough air may require continual adjustment of the brakes to keep the canopy overhead.

Accurate control of airspeed not only helps prevent closures but also improves performance. Airspeed can be monitored by listening to the noise the air makes rushing through the risers and adjusting the brakes to maintain a constant noise. This method has the special advantage of requiring no visual information and so can be applied in cloud.

This is a compromise. Fast enough for the brakes to be effective but with some brake on to 'feel' the canopy and reduce closures. With modern canopies this may be about max. glide.

The angle of attack is low and the turbulence only needs to reduce it by a little to cause a closure. Excess speed does, however, increase inflation pressure and the effectiveness of a pump.

Keeping a light pressure on the brakes in itself provides some limitation of closures and enables the pilot to detect incipient closures. Loss of tension in the brake lines gives us an effective 'tuck alarm' allowing an immediate response without checking the canopy. A moderate pump for partial loss of tension and a strong one for complete loss. With practice this becomes reflexive and less tiring.

Following a pump it is important to let brake off quickly to recover lost airspeed and be ready for further closures. In rough air a tense pilot may invountarily retain more and more brake each time they give a pump. This is extremely dangerous and may eventually result in a stall or spin.

Any canopy, even one with all A's (old Acpuls system) can deflate in

rough air.

The danger is greater if the pilot;

• Fails to notice or react to the closure.
• Flies canopy which is too difficult.
• Fails to anticipate a closure.
• Fails to re-inflate the canopy quickly enough.
• Flies too close to the hill.

• As a priority steer to avoid crashing.
• Limit braking action to avoid stalling and conserve airspeed.
• Re-inflate canopy whilst continuing to steer.

• Modern canopies generally require prolonged deep pumps to re-inflate. Older canopies required firm pumps of short duration. Pilots should to use the minimum necessary intervention but ensure that their pumps are strong and deep enough to be effective. Don't just flap your arms like a chicken.



• If more than one pump is required it may be necessary to wait a short while to recover airspeed between each one.



• If possible the weight should be kept on the inflated side. Cross braced harnesses help this.



• It may not always be possible to prevent a canopy with a severe asymmetric deflation (>50%) from turning altogether. Excessive brake applied to the inflated side may cause a stall, spin, or even a twist.



• In a strong thermal the safest place is usually in the core and remaining there may take priority over pumping out minor tucks which will probably come out without pilot intervention.



• Careful adjustment of the brake line lengths will help with closure control.



• Maladjustment of the harness may worsen the effects of closures. Risers too close together or overtight cross bracing may give a false impression of security and increase the chances of a twist.



• The fully supine position increases the risk of a 'twist' because of the increased moment of inertia of the pilot about the vertical axis. An upright posture will also help the pilot to resist roll disturbances better.